The present invention relates to modified organopolysiloxanes and compositions containing them. More particularly, the invention relates to compounds in which carboxyl groups of heterocyclic compounds are combined with amino groups of amino-modified silicones, and compositions containing the above-described compounds and silicone oil. The above-mentioned compounds can thicken silicone oil and allow the silicone oil to gel, so that they can impart stability to products using the silicone oil and improve feeling and usability thereof. They can be therefore used in various industrial products, pharmaceutical preparations and cosmetics.
Recently, silicone oil, particularly low-viscosity silicone oil, has been compounded in many cosmetics because of its excellent extensibility, refreshing feeling, lubricity, water repellency and high safety.
However, silicone oil is generally poor in compatibility with other oils, so that it is difficult to prepare stable products containing it. Even when wax is added for obtaining stable gelatinous or emulsion-like products using the low-viscosity silicone oil as bases, stable products are not obtained. The use of crosslinked silicones raises the problem that sticky feeling remains while inherent refreshing feeling of the silicone oil is lost.
Then, stable bases have been desired which can allow the low-viscosity silicone oil to gel without impairing the inherent excellent extensibility and refreshing feeling thereof and which can be obtained by simple compounding, and in which the low-viscosity silicone oil is not separated and not discharged from the resulting compositions.
As a result of intensive investigation under such situations, the present inventors have discovered that modified organopolysiloxanes in which carboxyl groups of heterocyclic compounds are combined with amino groups of amino-modified silicones can allow silicone oil to stably gel, thus completing the invention.
That is to say, the invention provides:
(1) A modified organopolysiloxane in which a carboxyl group of a heterocyclic compound having a carboxyl group and containing a nitrogen atom as a heteroatom is combined with an amino group of an amino-modified silicone;
(2) The modified organopolysiloxane described in (1), in which the heterocyclic compound is a 6-membered heteromonocyclic compound;
(3) The modified organopolysiloxane described in (2), in which the 6-membered heteromonocyclic compound is orotic acid: 
(4) The modified organopolysiloxane described in (2), in which the 6-membered heteromonocyclic compound is pyridinecarboxylic acid: 
(5) The modified organopolysiloxane described in (1), (2), (3) or (4), in which the amino-modified silicone is a silicone represented by formula (3): 
wherein R1 to R3, which may be the same or different, represent alkyl groups each having 1 to 22 carbon atoms, phenyl groups, naphthyl groups or polyoxyalkylene groups; at least one of R4 to R6 is a group represented by formula (4):
H2Nxe2x80x94"Parenopenst"xe2x80x94R7xe2x80x94NHxe2x80x94"Parenclosest"sxe2x80x94R8xe2x80x94xe2x80x83xe2x80x83(4)
(wherein R7 and R8 represent alkylene groups each having 1 to 6 carbon atoms, and S represents 0 or 1), and the remaining groups, which may be the same or different, represent alkyl groups each having 1 to 22 carbon atoms, phenyl groups, naphthyl groups or polyoxyalkylene groups; and m and n each represent numbers of 1 or more;
(6) A method for producing the modified organopolysiloxane described in (1), (2), (3), (4) or (5), which comprises reacting a heterocyclic compound having a carboxyl group and containing a nitrogen atom as a heteroatom with an amino-modified silicone in water;
(7) A method for producing the modified organopolysiloxane described in (1), (2), (3), (4) or (5), which comprises reacting a heterocyclic compound having a carboxyl group and containing a nitrogen atom as a heteroatom with an amino-modified silicone in a mixture of water and silicone oil;
(8) A composition comprising the modified organopolysiloxane described in (1), (2), (3), (4) or (5) and silicone oil;
(9) An emulsion composition obtained by reacting a heterocyclic compound having a carboxyl group and containing a nitrogen atom as a heteroatom with an amino-modified silicone in water and silicone oil, and stirring the resulting system; and
(10) A gelling agent which is consisted of the modified organopolysiloxane in (1) to (5).